The invention relates to a tilt-swivel head for optical apparatus, especially for surveillance cameras, having a housing, a mounting base for the housing, and operating means for swiveling the apparatus about a first, vertical axis AS-AS and corresponding shaft connecting the housing and the mounting base to one another, and for tilting it about a second, horizontal axis AN-AN and corresponding shaft connecting the housing to a support for the apparatus. The housing has a tubular extruded section which is closed with a cover at each end.
Such tilt-swivel heads are used principally in the field of the video surveillance of buildings and apparatus by means of self-contained video systems. The optical apparatus under discussion here are not, however, just video cameras but also searchlights, aiming devices etc.
It is not just video cameras that have a considerable weight due to their high-speed, long-range zoom objectives, but also searchlights or batteries of searchlights, whose center of gravity as a rule also is at a considerable distance from each of the two pivot axes. If it is desired to increase the number of the optical apparatus, the mechanical conditions are worsened, and it is to be taken into account that the pivoting support of the optical apparatus is a cantilevered support.
German Patent 38 11 523 discloses a housing for tilt-swivel heads which consists of a bottom part and an upper part joined together at a diagonal dividing line. The housing is rotatably joined to a mounting base in the form of a plate which in turn can be fastened on a bracket or to the ceiling of a building. Such housings, consisting of metal, are extremely expensive to manufacture, since they are needed in various sizes and with various equipment, so that it is necessary to have on hand a number of molds, dies or the like for each size of housing. If in this case a saving in the mold is achieved, a greater number of finishing steps are called for, including smoothing and painting. The round inside cross section of the bottom part of the housing limits the equipment it can contain, and especially limits the installation of rectangular plates and other components of square or rectangular profile.
It is also known, in the case of a tilt-swivel head, to manufacture the housing and mounting base from sections of tubular extrusions closed at both ends with a flat cover. The axes of the tubular extrusions of the housing and mounting base are aligned with and perpendicular to one another, so that a tower-like structure is formed. The motor controlling the swiveling movement is disposed in the mounting base, and the motor controlling the tilting movement is disposed in the housing. The mounting base thus is given an appreciable height, and the space limitations within the extruded sections make the installation of the mechanical, electrical and electronic parts difficult. The separate containment of the motors and gears also calls for a considerable amount of space. For this reason, this kind of design has been used heretofore only at the bottom end of the possible size range.
The invention therefore is addressed to the problem of devising a tilt-swivel head of the kind described in the beginning and above, whose principle of construction is appropriate even for heavy-duty models, and permits a simple and space-saving installation of the actuators and corresponding electrical and electronic components. Also, the principle of design is to permit a great range of different housing dimensions without making it necessary to stock a large number of different extruded cross sections.
The term, "actuators," as used herein is intended to refer to any mechanical and electrical actuating systems making it possible to send commands to the optical apparatus. Such actuators may consist, for example, of miniature electric motors with appropriate gearing, which can be in the form of spur gears or worm gearing, so that self-locking, for example, will be provided. It is also possible, however, to provide so-called multi-pole motors as actuators, or stepping mechanisms, all the way up to ultrasonic drives. Position indicators can also be associated with the actuators so that the reaching of a particular position can be known.
For the solution of the stated problem, such tilt-swivel heads in accordance with the invention are characterized by the fact that:
a) The extruded section is mounted with a horizontal axis AP-AP, with its cut ends vertical, and it has a horizontal side and at least one vertical side, which together with the other parts of the wall of the extruded section form a tubular hollow body. PA0 b) The vertical pivot shaft corresponding to axis AS-AS passes through the horizontal bottom of the extruded section and is supported on the latter. PA0 c) The horizontal tilt shaft corresponding to axis AN-AN passes through the vertical part of the extruded section and is supported thereon, and PA0 d) The two covers with vertical sealing surfaces are fastened on the end surfaces of the extruded section and enclose the actuators between them and the extruded section.
An extruded section of this kind can be cut to length from an extruded stock of appropriate cross section, thus constituting a first possibility for variation in regard to the housing width. As regards its surface, the extruded section can be improved at low cost, e.g., by anodizing or it can be coated with plastic, without requiring complex coating processes. In particular, the smoothing operations so often required in the case of castings can be avoided. The extruded section which is open at both ends when assembly begins, and preferably is in the form of a flat frame, permits virtually unlimited access from both ends, so that the installation of the actuators and corresponding electrical and electronic components is facilitated. Since the actuators for both axes can accommodated, a very compact installation can be made, so that more powerful actuators and motors can be used without the need for greater housing dimensions. The extruded stock can consist not only of an aluminum alloy but also of an extrudable plastic or plastic mixture, with and without fiber reinforcement.
A second and much more interesting possibility of varying the housing dimensions is provided by the variable width of the geometrical shape of the two covers of the housing. Depending on the length of the extruded section, they can be in the form of flat plates with plane-parallel surfaces, which are screwed to the vertical end surfaces or sealing surfaces of the extruded section.
To special advantage, the two housing covers can also be box-like and/or domed, so that the extruded section itself can be kept correspondingly short, which greatly facilitates the installation of the parts. The housing covers are given great stability of shape by their configuration, which together with the stability of the extruded section makes up an extremely distortion-resistant housing.
Dies for extruders entail but a fraction of the cost of, for example, die-casting dies. Also, molds for the injection-molding of the housing covers, preferably from a fiber-reinforced plastic, are comparatively cheap to produce. However, covers consisting of flat or deep-drawn metal or plastic can also be used.
It is especially advantageous if the upright portion of the extruded section bears the first journal for the tilt shaft corresponding to axis AN-AN and, with a slight separation therefrom, bears a plate in which the second journal for the tilt shaft corresponding to axis AN-AN is situated, and on whose side facing away from the upright portion a motor controlling the tilting movement is fastened, and gearing for the tilt shaft corresponding to axis AN-AN is disposed in the space between.
It is furthermore advantageous if the horizontal part of the extruded section bears the first bearing for the AS-AS pivot shaft and, separated from it by a small space, a plate in which the second bearing for the AS-AS pivot shaft is situated, and on whose side facing away from the horizontal part a motor is fastened for controlling the swiveling movement, parts of a reduction gearing for the AS-AS pivot shaft being disposed in the space between.
The horizontal and vertical sides of the extruded section serve to a certain extent, in this case, as second plates for the mounting of the gears.
Other advantageous developments of the subject matter of the invention will appear in the secondary claims.